Unit body vibrating screen

ABSTRACT

A vibrating screen is disclosed which moves by gyrating in a circular path about a horizontal axis. The screen has an inclined body with an elevated feed end defined between a pair of side walls spaced apart by a plurality of rigid tubular cross members. One of the tubular cross members, centrally located, has a diameter large enough for a drive shaft and associated bearings to be mounted therein. Each of the tubular cross members projects on each end into an aperture cut in the adjacent side wall where each is joined to the adjacent side wall by a weld around the entire circumference thereof to provide an integral unitary assembly of light weight, great strength, high natural frequency and with the weld path joining the cross members to the side walls having a configuration which is the same, i.e., circular, as the path of motion of the screen in vertical planes defined by the weld paths.

United States Patent Hahn [4 1 Sept. 26, 1972 [54] UNIT BODY VIBRATINGSCREEN 2,702,634 2/1955 Roubal ..209/367 72 I t: Mth P.Hah W t ,W. I 1or a ew auwa 08a 18 Primary Examiner-Tim R. Miles [73] Assignee:Allis-Chalmers Manufacturing Com- Attorney-Arthur M. Streich, Robert B.Benson and pany, Milwaukee, Wis. John P, Hines [22] Filed: I Aug. 28,1970 I ABSTRACT [21] Appl 67331 A vibrating screen is disclosed whichmoves by gyrating in a circular path about a horizontal axis. The [52]US. Cl..... ..209/326, 209/3665 screen has an inclined body with anelevated feed end [51] Int. Cl. ..B07b 1/36 fined between a pair of sidewalls spaced apart by a [58] Field of Search ..209/366.5, 326, 332, 367plurality f rigid tubular cross members. One of the tubular crossmembers, centrally located, has a diame- 5 References Cited ter largeenough for a drive shaft and associated bearings to be mounted therein.Each of the tubular UNITED STATES PATENTS cross members projects on eachend into an aperture 313 765 M1943 Parks 209/326 cut in the adjacentside wall where each is joined to l949703 3/l934 g 'g "209/326 theadjacent side wall by a weld around the entire cir- 2964186 12/1960Ferrara B66 5 cumference thereof to provide an integral unitary as-1920972 8/1933 D 'T' "209/3665 sembly of light weight, great strength,high natural 349l881 l 1970 i "209/366'5 frequency and with the weldpath joining the cross G953 members to the side walls having aconfiguration ,Over f which is the same, i.e., circular, as the path ofmotion of the screen in vertical planes defined by the weld th 2,292,3278/1942 Lincoln; pa 8 v 2.75 1,080 6/1956 G-leiser ..209/367 3 Claims, 5Drawing Figures PATENTED SEPZS I97? 3.693. 793

1 UNIT BODY VIBRATING SCREEN BACKGROUND OF THE INVENTION Examples ofscreens which. gyrate about an axis passing transversely through sidewalls of a screen body include such as is shown in U.S. Pat. No.2,292,327 of 1942; U.S. Pat. No. 2,313,765 of 1943; U.S. Pat. No.2,702,634 of 1955 and U.S. Pat. No. 2,751,080 of I956. Each ofthesepatents disclose such a screen in which a massive vibrator driveshaft-is journaled in bearing assemblies which are in turn journaled ina housing around the drive shaft. The housing, the hearing assembliesorboth are bolted to screen body side walls and the shaft, the bearingassemblies and the housing are carried by. the screen body. The sidewalls of such screen bodies are bolted or riveted to cross beams. Screenconstructed as shown in such prior art patents, when installed or aftera period of operation, may have a natural frequency which is too low,that is if the natural frequency of the screen is not well above theoperating frequencyimposed thereon by the operation of the vibratordrive shaft, the screen will be subjected to violent vibration which candamage a screen or reduce its useful life. Usual solutions to suchproblems known to. the prior art involve adding braces or heavier bodycomponents to stiffen the body. While such techniques are successful inraising the natural SUMMARY OF THE PRESENT INVENTION It is among theobjects of the present invention to provide a new and improvedlightweight screen of great strength and high natural frequency wellabove operating frequency of the screen.

According to a preferred embodiment of the present invention screen bodyside walls are spaced apart by a plurality of rigid tubular crossmembers. One of the tubular cross members, centrally located withrespect to both side walls, has a diameter larger than all others andlarge enough for a drive shaft and associated hearings to be mountedtherein. The drive shaft carries eccentric mass counterbalancing thescreen body relative to an axis transverse to both side walls and aboutwhich axis the screen gyrates. Each of the tubular cross membersprojects on each end into an aperture cut in the adjacent side wallwhere each cross member is joined to the adjacent side wall where eachcross member is joined to the adjacent side wall by a weld around theentire circumference thereof to provide an integral unitary assembly oflight weight, great strength, high natural frequency and with the weldpath joining the cross members to the side walls having a configurationwhich is the same, i.e., circular, as the path of motion of the screenin vertical planes defined by the weld paths. At least one of thetubular cross members between the shaft enclosing cross member and eachend of the screen body, project on both ends through and outwardly ofboth side walls to provide support arms for the screen which are aunitary part of a side wall spacing cross member.

Other features and objects of the invention that have been attained willappear from the more detailed description to follow with reference to anembodiment of the present invention shown in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 of the accompanying drawingshows a side elevation of a vibratory screen according to the presentinvention;

FIG. 2 is an end view of the screen of FIG. 1; and

FIGS. 3, 4 and 5 are fragmentary views showing details of theconstruction of the screen of FIG. I to enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT cross members 20. One of thetubular cross members a is located centrally with respect to both sidewalls, 15, 16. The tubular cross member 20a has a larger diameter thanall other of the cross members 20 and cross member 20a has arrangedwithin it a drive shaft 22 journaled in bearings 24. The drive shaft-22carries eccentric mass 25 counterbalancing the screen bodyrelative to anaxis X-X' transverse to side walls l5, l6 and about which (axis X--X')the screen gyrates with substantially all points on the screen assemblymoving to trace, in a vertical plane, a circular path of motion. Balancewheels 26 may be mounted on shaft 22 outboard of walls 15, 16 andweights 27, 28 may be attached thereto to provide eccentriccounterbalancing mass to supplement the mass 25 or as an alternate tomass 25. The drive shaft 22 is driven by a motor 30 through belts 31connected to drive a pulley 32 mounted on one end of the drive shaft 22.The screen body 10 is shown as being provided with two decks or screensurfaces 33, 34. The screen surfaces 33, 34 are supported at the feedand discharge ends 12, 13 by beams 35 and at locations intermediate thefeed and discharge ends by the tubular cross members 20.

In the assembly of a screen as shown in FIGS. 1 and I 2, apertures inFIGS. 3, 4 and 5) for receiving end portions of the tubular crossmembers 20 are cut in both side walls 15, 16. The manner in which thetubular cross members 20 are connected to the side walls 15, 16 will bedescribed with reference to FIGS. 3, 4 and 5.

Referring to FIG. 3, an aperture 40a in side wall 16 is shown fittedwith an annular collar 41 welded thereto for receiving an end portion ofthe large diameter tubular cross member 200. The end portion of crossmember 20a projects axially part way within collar 41. Cross member 20ais connected to collar 41 by an annular weld 42a connecting the outercircumference of cross member 20a to an adjacent vertical surface 44 ofcollar 41 and by an annular weld 43a connecting the adjacent end ofcross member 20a to an inner circumferential surface 45 of collar 41.

As shown in FIGS. 1 and 2 oneof the cross members 20b at each end of thescreen body serves to connect the springs 11 to the screen body 10. Themanner in which the cross members 20b are connected to the screen body10 and to the springs 11 is shown in FIG. 4. As shown in FIG. 4, an endportion of a cross member 20b projects through aperture 40b and beyondside wall 16 and a bracket 46 which is mounted on top of spring 11.Cross member 20b is connected to side wall 16 by annular welds 42b and43b. All other tubular cross members 20, that is all tubular crossmembers 20 except cross member 20a and a pair of cross members 20b, areconnected to the side walls 15, 16 as shown in H6. 5. As shown inFIG.'5, a cross member 20 projects through aperture 40 and beyond anouter surface 48 of side wall 16 and an annular weld 42 connects thecross member 20 to the side wall 16.

By the construction that has been described a unitary screen body 10 isprovided of which side walls 15, 16

and all tubular cross members are integral parts. The screen body 10 ofapertured side walls 15, 16 and tubular cross members 20 is of lightweight and great strength. The rigidity of the screen body 10 providedby such construction provides a screen body with a high naturalfrequency, well above the operating frequency of the screen about theaxis XX'. The screen body 10 is assembled with welds 42, 43 that followa circular path, as does every point on side walls 15, 16in the verticalplanes defined by the welds, during operation of drive shaft 22.

From the foregoing detailed description of the present invention it hasbeen shown how the objects of the present invention have been attainedin a preferred manner. However, modification and equivalents of thedisclosed concepts such as readily occur to those skilled in the art areintended to be included in the scope of this invention. Thus, the scopeof the invention is intended to be limited only by the scope of theclaims such as are or may hereafter be, appended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a vibrating screen arranged to gyrate in a circular path about ahorizontal axis of gyration and having a screen body with a feed end anda discharge end definedbetween a pair of horizontally spaced verticalside walls, and each side wall defining a centrally located aperturetherethrough, said apertures being in horizontal and vertical register,a vibrator drive shaft arranged within the side wall apertures andhaving a journal on each end concentric thereto and carrying eccentricmass counterbalancing the screen body relative to said axis of gyration,and a-bearing assembly mounted around each journal and projecting to theadjacent aperture, the improvement comprising:

A. the side walls of the screen body being spaced apart by a pluralityof rigid tubular cross members;

Bd ri of the cross members being of greater diameter than the other ofsaid cross members and said larger diameter cross member being mountedabout said vibrator drive shaft and bearing; and

C. each end of each said cross member being joined to an adjacent sidewall by a weld around the entire circumference thereof to provide anintegral unitary assembly of great strength and high natural frequencyand with the welds having a circular configuration corresponding to thecircular path of motion of the screen in vertical planes defined by thewelds around the tubular cross members.

2. A vibrating screen according to claim 1 in which at least one tubularcross member between the drive shaft and said feed end and at least onetubular cross member between the drive shaft and said discharge endproject on both ends thereof through and outwardly of both side walls toprovide support arms for the screen which are a unitary part of a sidewall spacing cros member.

3. A vibrating screen according to claim 1 in which the side walls eachdefine a plurality of apertures therein with one of said apertures beingprovided for the adjacent end of each tubular cross member, and eachtubular cross member projects on both ends thereof through one of theapertures in register therewith.

1. In a vibrating screen arranged to gyrate in a circular path about ahorizontal axis of gyration and having a screen body with a feed end anda discharge end defined between a pair of horizontally spaced verticalside walls, and each side wall defining a centrally located aperturetherethrough, said apertures being in horizontal and vertical register,a vibrator drive shaft arranged within the side wall apertures andhaving a journal on each end concentric thereto and carrying eccentricmass counterbalancing the screen body relative to said axis of gyration,and a bearing assembly mounted around each journal and projecting to theadjacent aperture, the improvement comprising: A. the side walls of thescreen body being spaced apart by a plurality of rigid tubular crossmembers; with B. one of the cross members being of greater diameter thanthe other of said cross members and said larger diameter cross memberbeing mounted about said vibrator drive shaft and bearing; and C. eachend of each said cross member being joined to an adjacent side wall by aweld around the entire circumference thereof to provide an integralunitary assembly of great strength and high natural frequency and withthe welds having a circular conFiguration corresponding to the circularpath of motion of the screen in vertical planes defined by the weldsaround the tubular cross members.
 2. A vibrating screen according toclaim 1 in which at least one tubular cross member between the driveshaft and said feed end and at least one tubular cross member betweenthe drive shaft and said discharge end project on both ends thereofthrough and outwardly of both side walls to provide support arms for thescreen which are a unitary part of a side wall spacing cross member. 3.A vibrating screen according to claim 1 in which the side walls eachdefine a plurality of apertures therein with one of said apertures beingprovided for the adjacent end of each tubular cross member, and eachtubular cross member projects on both ends thereof through one of theapertures in register therewith.